Improvement in extension-keys



w. T. MuNaEn.

Extension-Keys. i No'. 146,468. l Patentedlammnsm.

UNITED STATES PATENT OFFICE.

WALLACE T. MUNGER, or NEw BRITAIN, CONNECTICUT, AssreNoR Tour. AND E.coRBIN, or SAME PLACE.

IMPROVEMENT IN EXTENSION-KEYS.`

Specification forming part of Letters Patent No. 146,468, dated January13, 1874 application filed December 23, 1873.

To all whom 'it may concern:

Be it known that I, WALLACE T. MUNGER, of New Britain, in the county ofHartford and State of Connecticut, have invented an Improvement inExtension-Keys for Door-Locks, of which the following is aspecification:

Keys have been made in which there is a joint in the stem, and otherswith a telescopic shank.

My present invention is made for extending a plate-key; and it consistsin a slotted case with a bow at one end, that is mortised for the end ofthe key-shank, and a pin upon the keyshank forms a stop to the key, andlimits the movement of the same in the case in both directions.

In the drawing, Figure 1 is an extension of the key as extended. Fig. -2shows the same as shut up. Fig. 3 is a cross-section of the slottedcase. K

The plate-key a is made with the bits of usual character. The shank b,instead of being made with a bow, as usual, is provided with aspring-catch, c, and a stop-pin, i. The Ilat case d is made with a bow,e, at one end, and it is hollow, so that the key-shank b can slidefreely therein, and the bow e is mortised at s for the end of the shankto pass to the top of the bow when the key is shutor slipped back. Bythis means the key is made as short as possible. The stop-pin i slidesin the slot o ofthe case, and determines the distance that the key-shankcan be drawn out, and also forms a stop in closing the key, by arrestingthe movement when coming into contact with the inner part of the bow, asseen in Fig. 2.

This construction of key is very strong, simple, durable, and compact;and when drawn out the spring c retains the shank in an cxtendedposition.

I claim as my invention- The at case d, made hollow and slotted, andhaving at one end the bow e, with a mortise, s, in combination with theplate-key a.sl1ank b, spring o, and stop-pin i, substantially as and forthe purposes set forth.

Signed by me this 12th day of December, A.

W. T. MUN GER. Witnesses CHARLES PEGK, EDWD. L. PRIOR.

